How to Use Tesseract with C# for Image Text Extraction

Introduction

The OCR library is a software that converts documents of various natures into editable and searchable information. It converts scanned images, PDFs, and digital camera shots into editable and searchable data. It is widely applied in converting printed documents to digital format for editing, searching, and archiving, lessening the amount of space consumed by documents. OCR plays a humongous part in automating data entry, thereby saving businesses and organizations ample time by curtailing the human resources used. It is a process employing sophisticated machine learning and pattern recognition methods to read text precisely from images.

Recent developments concerning OCR have made it more accurate, thereby supporting additional languages and complicated scripts like the Arabic script. Extremely important in finance, healthcare, law, and education, OCR was a necessary tool whereby the mass processing of a number of printed documents was required quickly. In this paper, Tesseract will be utilized to OCR images in multiple languages.

How to Use Tesseract OCR ?

1. Installing the IronOCR/Tesseract package.
2. To further initialise the OCR engine, an instance of the class IronTesseract will be generated.
3. After defining the location of the image file you wish to process, build an OCRInput object.
4. Proceed to OCR the input image using the IronTesseract instance’s Read function.
5. Display the result on the console.

What is Tesseract?

Tesseract is an open Optical Character Recognition engine developed by Hewlett-Packard and further developed by Google. It is famous for its precision and adaptability, which makes it one of the most popular OCRs. Tesseract has script detection, supports text recognition in many languages, and can recognize more than one language; thus, it is normally utilized for multilingual document projects and requires trained data.

To render characters, words, and sentences that are ultimately converted to machine-readable text, the Tesseract OCR engine employs information from any pixel within the image to learn patterns. Tesseract is capable of producing text in plain text, HTML, and searchable PDF as it is able to read many types of bitmap image files, including TIFF, JPEG, and PNG.

One of the most important assets of Tesseract is that it can be taught to be font-sensitive or to new languages. It is also extensively used in various programs, ranging from simple text pulling out to more complex operations in digitizing historic documents, handling invoices, or even accessibility packages that enable the blind to read.

Creating a New Project in Visual Studio

Launch Visual Studio. When the application opens, select the “file menu.” The “new project” option is located in the “file menu.” Click on “new project,” then “Console Application.” In this article, we’ll be using a console application to create PDF files.

Enter the file path and the project name in the text boxes. Then, as seen in the image below, click the Create button and choose the .NET Framework you require.

Once the version has been selected, Visual Studio will create the structure of the program. It will open the file program.cs to insert code and execute/run the application if you choose the console, Windows, or web versions.

Install Tesseract OCR For .NET

The first step is to install the Tesseract OCR software on your machine. The Tesseract installation, including the tessdata folder, can be located in the official Tesseract GitHub source here: https://github.com/tesseract-ocr/tesseract.

For NuGet, choose Tools -> Package Manager -> Select Manage NuGet Packages for Solution within your Visual Studio project in order to launch the NuGet Package Manager. The “Tesseract” or “Tesseract.NET” package can then be located by searching for “Tesseract” in the NuGet Package Manager. The package can then be added to your project by choosing it and clicking the Install button.

OCR Image using Tesseract

After you have installed the Tesseract.NET wrapper, you must configure Tesseract in your C# application by specifying the path to the Tesseract OCR executable and language data files, adhering to the permissions of your language. Below is an example:

Importing Required Namespaces

using Tesseract;        

Imports the Tesseract OCR library into the C# application, making its classes and methods accessible. This makes it possible for the developer to utilize functionality such as loading images, initializing the OCR engine, and reading text from images using Optical Character Recognition within the application.

Setting the Tesseract Data Path

string tessDataPath = @"./tessdata";        

specifies the file path to the Tesseract language data directory. The @”./tessdata” indicates a relative path to a directory named tessdata, which should include traineddata files (e.g., eng.traineddata) needed for language identification by the OCR engine, adhering to applicable law.

Loading the Input Image

string imagePath = @"path_to_your_image.png";
using (var img = Pix.LoadFromFile(imagePath))        

This line of code finds the path where an image file is present and loads it into processing with the help of Tesseract’s OCR engine. The image is stored in a variable, and the using statement guarantees disposing of the image after usage so that resources and memory can be utilized effectively.

using (var engine = new TesseractEngine(tessDataPath, "eng+spa+fra", EngineMode.Default))        

using (var page = engine.Process(img))
{
    string text = page.GetText();
    Console.WriteLine("Recognized Text:");
    Console.WriteLine(text);
}        

using System;
using System.Drawing;
using Tesseract;

class Program
{
    static void Main()
    {
        // Set the path to the Tesseract data files (traineddata files)
        string tessDataPath = @"./tessdata"; // Ensure this directory contains the language data files

        // Load the image
        string imagePath = @"path_to_your_image.png";
        using (var img = Pix.LoadFromFile(imagePath))
        {
            // Add tesseract languages into engine
            using (var engine = new TesseractEngine(tessDataPath,  "eng+spa+fra", EngineMode.Default))
            {
                using (var page = engine.Process(img))
                {
                    // Extract the text
                    string text = page.GetText();
                    Console.WriteLine("Recognized Text:");
                    Console.WriteLine(text);
                }
            }
        }
    }
}        

Install-Package IronOcr
Install-Package IronOcr.Languages.French
Install-Package IronOcr.Languages.Spanish        

using IronOcr;

class Program
{
    static void Main(string[] args)
    {
        // Initialize IronTesseract engine
        var Ocr = new IronTesseract();
        
        // Add multiple languages
        Ocr.Language = OcrLanguage.English + OcrLanguage.Spanish + OcrLanguage.French;
        
        // Path to the image
        var inputFile = @"pathtoyourimage.png";
        
        // Read the image and perform OCR
        using (var input = new OcrInput(inputFile))
        {
            // Perform OCR
            var result = Ocr.Read(input);
            
            // Display the result
            Console.WriteLine("Text:");
            Console.WriteLine(result.Text);
        }
    }
}